The present invention relates to a high D.C. voltage generating apparatus for the power source of a plasma generating apparatus by nuclear fusion, for example.
In a high D.C. voltage generating apparatus for the power source of a plasma generating apparatus by nuclear fusion, etc., it is necessary to reduce a D.C. current supplied to an inductive lead in an extremely short time compared with the time constant of the load, thereby generating in a short time a high D.C. voltage in the order of 100 times of the initial supplying voltage.
As this type of high D.C. voltage generating apparatus, there may be considered an apparatus in which a D.C. current is directly supplied to an inductive load from a thyristor converter means acting as an inverter and the thyristor converter means generates a negative voltage, thereby generating a high voltage across the load. When such an apparatus is large in scale, an extraordinarily large capacity is required. The apparatus of such a large capacity, however, encounters a difficulty in manufacturing thereof from a technical and economic viewpoint.
For solving such problems, there may be considered a high D.C. voltage generating apparatus additionally provided with a D.C. breaker means between the thyristor converter means and the load. When this apparatus is large in scale, however, there also exists a problem in producing the D.C. breaker means due to its current-carrying capacity and its breaking or interrupting capacity. There may be considered another high D.C. voltage generating apparatus provided with a switching means using thyristors in place of such a D.C. breaker means. But, this switching means requires a large current and high voltage capacity, and thus the manufacture of it is difficult.